/******************************************************
Transaction system

(c) 1996 Innobase Oy

Created 3/26/1996 Heikki Tuuri
*******************************************************/

#ifndef trx0sys_h
#define trx0sys_h

#include "univ.i"

#include "trx0types.h"
#include "mtr0mtr.h"
#include "mtr0log.h"
#include "ut0byte.h"
#include "mem0mem.h"
#include "sync0sync.h"
#include "ut0lst.h"
#include "buf0buf.h"
#include "fil0fil.h"
#include "fut0lst.h"
#include "fsp0fsp.h"
#include "read0types.h"

/* In a MySQL replication slave, in crash recovery we store the master log
file name and position here. We have successfully got the updates to InnoDB
up to this position. If .._pos is -1, it means no crash recovery was needed,
or there was no master log position info inside InnoDB. */

extern char trx_sys_mysql_master_log_name[];
extern ib_longlong trx_sys_mysql_master_log_pos;

/* If this MySQL server uses binary logging, after InnoDB has been inited
and if it has done a crash recovery, we store the binlog file name and position
here. If .._pos is -1, it means there was no binlog position info inside
InnoDB. */

extern char trx_sys_mysql_bin_log_name[];
extern ib_longlong trx_sys_mysql_bin_log_pos;

/* The transaction system */
extern trx_sys_t *trx_sys;

/* Doublewrite system */
extern trx_doublewrite_t *trx_doublewrite;
extern ibool trx_doublewrite_must_reset_space_ids;
extern ibool trx_sys_multiple_tablespace_format;

/********************************************************************
Creates the doublewrite buffer to a new InnoDB installation. The header of the
doublewrite buffer is placed on the trx system header page. */

void trx_sys_create_doublewrite_buf(void);
/*================================*/
/********************************************************************
At a database startup initializes the doublewrite buffer memory structure if
we already have a doublewrite buffer created in the data files. If we are
upgrading to an InnoDB version which supports multiple tablespaces, then this
function performs the necessary update operations. If we are in a crash
recovery, this function uses a possible doublewrite buffer to restore
half-written pages in the data files. */

void trx_sys_doublewrite_init_or_restore_pages(
    /*======================================*/
    ibool restore_corrupt_pages);
/********************************************************************
Marks the trx sys header when we have successfully upgraded to the >= 4.1.x
multiple tablespace format. */

void trx_sys_mark_upgraded_to_multiple_tablespaces(void);
/*===============================================*/
/********************************************************************
Determines if a page number is located inside the doublewrite buffer. */

ibool trx_doublewrite_page_inside(
    /*========================*/
    /* out: TRUE if the location is inside
    the two blocks of the doublewrite buffer */
    ulint page_no); /* in: page number */
/*******************************************************************
Checks if a page address is the trx sys header page. */
UNIV_INLINE
ibool trx_sys_hdr_page(
    /*=============*/
    /* out: TRUE if trx sys header page */
    ulint space,    /* in: space */
    ulint page_no); /* in: page number */
/*********************************************************************
Creates and initializes the central memory structures for the transaction
system. This is called when the database is started. */

void trx_sys_init_at_db_start(void);
/*==========================*/
/*********************************************************************
Creates and initializes the transaction system at the database creation. */

void trx_sys_create(void);
/*================*/
/********************************************************************
Looks for a free slot for a rollback segment in the trx system file copy. */

ulint trx_sysf_rseg_find_free(
    /*====================*/
    /* out: slot index or ULINT_UNDEFINED
    if not found */
    mtr_t *mtr); /* in: mtr */
/*******************************************************************
Gets the pointer in the nth slot of the rseg array. */
UNIV_INLINE
trx_rseg_t *trx_sys_get_nth_rseg(
    /*=================*/
    /* out: pointer to rseg object, NULL if slot
    not in use */
    trx_sys_t *sys, /* in: trx system */
    ulint n);       /* in: index of slot */
/*******************************************************************
Sets the pointer in the nth slot of the rseg array. */
UNIV_INLINE
void trx_sys_set_nth_rseg(
    /*=================*/
    trx_sys_t *sys,    /* in: trx system */
    ulint n,           /* in: index of slot */
    trx_rseg_t *rseg); /* in: pointer to rseg object, NULL if slot
                       not in use */
/**************************************************************************
Gets a pointer to the transaction system file copy and x-locks its page. */
UNIV_INLINE
trx_sysf_t *trx_sysf_get(
    /*=========*/
    /* out: pointer to system file copy, page x-locked */
    mtr_t *mtr); /* in: mtr */
/*********************************************************************
Gets the space of the nth rollback segment slot in the trx system
file copy. */
UNIV_INLINE
ulint trx_sysf_rseg_get_space(
    /*====================*/
    /* out: space id */
    trx_sysf_t *sys_header, /* in: trx sys file copy */
    ulint i,                /* in: slot index == rseg id */
    mtr_t *mtr);            /* in: mtr */
/*********************************************************************
Gets the page number of the nth rollback segment slot in the trx system
file copy. */
UNIV_INLINE
ulint trx_sysf_rseg_get_page_no(
    /*======================*/
    /* out: page number, FIL_NULL
    if slot unused */
    trx_sysf_t *sys_header, /* in: trx sys file copy */
    ulint i,                /* in: slot index == rseg id */
    mtr_t *mtr);            /* in: mtr */
/*********************************************************************
Sets the space id of the nth rollback segment slot in the trx system
file copy. */
UNIV_INLINE
void trx_sysf_rseg_set_space(
    /*====================*/
    trx_sysf_t *sys_header, /* in: trx sys file copy */
    ulint i,                /* in: slot index == rseg id */
    ulint space,            /* in: space id */
    mtr_t *mtr);            /* in: mtr */
/*********************************************************************
Sets the page number of the nth rollback segment slot in the trx system
file copy. */
UNIV_INLINE
void trx_sysf_rseg_set_page_no(
    /*======================*/
    trx_sysf_t *sys_header, /* in: trx sys file copy */
    ulint i,                /* in: slot index == rseg id */
    ulint page_no,          /* in: page number, FIL_NULL if
                            the slot is reset to unused */
    mtr_t *mtr);            /* in: mtr */
/*********************************************************************
Allocates a new transaction id. */
UNIV_INLINE
dulint trx_sys_get_new_trx_id(void);
/*========================*/
/* out: new, allocated trx id */
/*********************************************************************
Allocates a new transaction number. */
UNIV_INLINE
dulint trx_sys_get_new_trx_no(void);
/*========================*/
/* out: new, allocated trx number */
/*********************************************************************
Writes a trx id to an index page. In case that the id size changes in
some future version, this function should be used instead of
mach_write_... */
UNIV_INLINE
void trx_write_trx_id(
    /*=============*/
    byte *ptr,  /* in: pointer to memory where written */
    dulint id); /* in: id */
/*********************************************************************
Reads a trx id from an index page. In case that the id size changes in
some future version, this function should be used instead of
mach_read_... */
UNIV_INLINE
dulint trx_read_trx_id(
    /*============*/
    /* out: id */
    byte *ptr); /* in: pointer to memory from where to read */
/********************************************************************
Looks for the trx handle with the given id in trx_list. */
UNIV_INLINE
trx_t *trx_get_on_id(
    /*==========*/
    /* out: the trx handle or NULL if not found */
    dulint trx_id); /* in: trx id to search for */
/********************************************************************
Returns the minumum trx id in trx list. This is the smallest id for which
the trx can possibly be active. (But, you must look at the trx->conc_state to
find out if the minimum trx id transaction itself is active, or already
committed.) */
UNIV_INLINE
dulint trx_list_get_min_trx_id(void);
/*=========================*/
/* out: the minimum trx id, or trx_sys->max_trx_id
if the trx list is empty */
/********************************************************************
Checks if a transaction with the given id is active. */
UNIV_INLINE
ibool trx_is_active(
    /*==========*/
    /* out: TRUE if active */
    dulint trx_id); /* in: trx id of the transaction */
/********************************************************************
Checks that trx is in the trx list. */

ibool trx_in_trx_list(
    /*============*/
    /* out: TRUE if is in */
    trx_t *in_trx); /* in: trx */
/*********************************************************************
Updates the offset information about the end of the MySQL binlog entry
which corresponds to the transaction just being committed. In a MySQL
replication slave updates the latest master binlog position up to which
replication has proceeded. */

void trx_sys_update_mysql_binlog_offset(
    /*===============================*/
    const char *file_name, /* in: MySQL log file name */
    ib_longlong offset,    /* in: position in that log file */
    ulint field,           /* in: offset of the MySQL log info field in
                           the trx sys header */
    mtr_t *mtr);           /* in: mtr */
/*********************************************************************
Prints to stderr the MySQL binlog offset info in the trx system header if
the magic number shows it valid. */

void trx_sys_print_mysql_binlog_offset(void);
/*===================================*/
#ifdef UNIV_HOTBACKUP
/*********************************************************************
Prints to stderr the MySQL binlog info in the system header if the
magic number shows it valid. */

void trx_sys_print_mysql_binlog_offset_from_page(
    /*========================================*/
    byte *page); /* in: buffer containing the trx system header page,
                 i.e., page number TRX_SYS_PAGE_NO in the tablespace */
#endif           /* UNIV_HOTBACKUP */
/*********************************************************************
Prints to stderr the MySQL master log offset info in the trx system header if
the magic number shows it valid. */

void trx_sys_print_mysql_master_log_pos(void);
/*====================================*/

/* The automatically created system rollback segment has this id */
#define TRX_SYS_SYSTEM_RSEG_ID 0

/* Space id and page no where the trx system file copy resides */
#define TRX_SYS_SPACE 0 /* the SYSTEM tablespace */
#define TRX_SYS_PAGE_NO FSP_TRX_SYS_PAGE_NO

/* The offset of the transaction system header on the page */
#define TRX_SYS FSEG_PAGE_DATA

/* Transaction system header */
/*-------------------------------------------------------------*/
#define TRX_SYS_TRX_ID_STORE            \
  0 /* the maximum trx id or trx number \
    modulo TRX_SYS_TRX_ID_UPDATE_MARGIN \
    written to a file page by any       \
    transaction; the assignment of      \
    transaction ids continues from this \
    number rounded up by .._MARGIN plus \
    .._MARGIN when the database is      \
    started */
#define TRX_SYS_FSEG_HEADER              \
  8 /* segment header for the tablespace \
    segment the trx system is created    \
    into */
#define TRX_SYS_RSEGS (8 + FSEG_HEADER_SIZE)
/* the start of the array of rollback
segment specification slots */
/*-------------------------------------------------------------*/

/* Max number of rollback segments: the number of segment specification slots
in the transaction system array; rollback segment id must fit in one byte,
therefore 256; each slot is currently 8 bytes in size */
#define TRX_SYS_N_RSEGS 256

#define TRX_SYS_MYSQL_LOG_NAME_LEN 512
#define TRX_SYS_MYSQL_LOG_MAGIC_N 873422344

/* The offset of the MySQL replication info in the trx system header;
this contains the same fields as TRX_SYS_MYSQL_LOG_INFO below */
#define TRX_SYS_MYSQL_MASTER_LOG_INFO (UNIV_PAGE_SIZE - 2000)

/* The offset of the MySQL binlog offset info in the trx system header */
#define TRX_SYS_MYSQL_LOG_INFO (UNIV_PAGE_SIZE - 1000)
#define TRX_SYS_MYSQL_LOG_MAGIC_N_FLD \
  0 /* magic number which shows       \
    if we have valid data in the      \
    MySQL binlog info; the value      \
    is ..._MAGIC_N if yes */
#define TRX_SYS_MYSQL_LOG_OFFSET_HIGH \
  4 /* high 4 bytes of the offset     \
    within that file */
#define TRX_SYS_MYSQL_LOG_OFFSET_LOW                           \
  8                               /* low 4 bytes of the offset \
                                  within that file */
#define TRX_SYS_MYSQL_LOG_NAME 12 /* MySQL log file name */

/* The offset of the doublewrite buffer header on the trx system header page */
#define TRX_SYS_DOUBLEWRITE (UNIV_PAGE_SIZE - 200)
/*-------------------------------------------------------------*/
#define TRX_SYS_DOUBLEWRITE_FSEG \
  0 /* fseg header of the fseg   \
    containing the doublewrite   \
    buffer */
#define TRX_SYS_DOUBLEWRITE_MAGIC FSEG_HEADER_SIZE
/* 4-byte magic number which
shows if we already have
created the doublewrite
buffer */
#define TRX_SYS_DOUBLEWRITE_BLOCK1 (4 + FSEG_HEADER_SIZE)
/* page number of the
first page in the first
sequence of 64
(= FSP_EXTENT_SIZE) consecutive
pages in the doublewrite
buffer */
#define TRX_SYS_DOUBLEWRITE_BLOCK2 (8 + FSEG_HEADER_SIZE)
/* page number of the
first page in the second
sequence of 64 consecutive
pages in the doublewrite
buffer */
#define TRX_SYS_DOUBLEWRITE_REPEAT \
  12 /* we repeat the above 3      \
     numbers so that if the trx    \
     sys header is half-written    \
     to disk, we still may be able \
     to recover the information */
#define TRX_SYS_DOUBLEWRITE_SPACE_ID_STORED (24 + FSEG_HEADER_SIZE)
/* If this is not yet set to
.._N, we must reset the
doublewrite buffer, because
starting from 4.1.x the space
id of a data page is stored to
FIL_PAGE_ARCH_LOG_NO_OR_SPACE_NO */
/*-------------------------------------------------------------*/
#define TRX_SYS_DOUBLEWRITE_MAGIC_N 536853855
#define TRX_SYS_DOUBLEWRITE_SPACE_ID_STORED_N 1783657386

#define TRX_SYS_DOUBLEWRITE_BLOCK_SIZE FSP_EXTENT_SIZE

/* Doublewrite control struct */
struct trx_doublewrite_struct
{
  mutex_t mutex;               /* mutex protecting the first_free field and
                               write_buf */
  ulint block1;                /* the page number of the first
                               doublewrite block (64 pages) */
  ulint block2;                /* page number of the second block */
  ulint first_free;            /* first free position in write_buf measured
                               in units of UNIV_PAGE_SIZE */
  byte *write_buf;             /* write buffer used in writing to the
                               doublewrite buffer, aligned to an
                               address divisible by UNIV_PAGE_SIZE
                               (which is required by Windows aio) */
  byte *write_buf_unaligned;   /* pointer to write_buf, but unaligned */
  buf_block_t **buf_block_arr; /* array to store pointers to the buffer
                               blocks which have been cached to write_buf */
};

/* The transaction system central memory data structure; protected by the
kernel mutex */
struct trx_sys_struct
{
  dulint max_trx_id; /* The smallest number not yet
                     assigned as a transaction id or
                     transaction number */
  UT_LIST_BASE_NODE_T(trx_t) trx_list;
  /* List of active and committed in
  memory transactions, sorted on trx id,
  biggest first */
  UT_LIST_BASE_NODE_T(trx_t) mysql_trx_list;
  /* List of transactions created
  for MySQL */
  UT_LIST_BASE_NODE_T(trx_rseg_t) rseg_list;
  /* List of rollback segment objects */
  trx_rseg_t *latest_rseg; /* Latest rollback segment in the
                           round-robin assignment of rollback
                           segments to transactions */
  trx_rseg_t *rseg_array[TRX_SYS_N_RSEGS];
  /* Pointer array to rollback segments;
  NULL if slot not in use */
  ulint rseg_history_len; /* Length of the TRX_RSEG_HISTORY
                         list (update undo logs for committed
                         transactions), protected by
                         rseg->mutex */
  UT_LIST_BASE_NODE_T(read_view_t) view_list;
  /* List of read views sorted on trx no,
  biggest first */
};

/* When a trx id which is zero modulo this number (which must be a power of
two) is assigned, the field TRX_SYS_TRX_ID_STORE on the transaction system
page is updated */
#define TRX_SYS_TRX_ID_WRITE_MARGIN 256

#ifndef UNIV_NONINL
#include "trx0sys.ic"
#endif

#endif
